Abstract
Tungsten-containing DLC(W-DLC) coatings with various concentrations are prepared by the chemical vapour deposition method and the magnetron co-sputtering method of tungsten metal target. The structures of the coatings is analysed by the transmission electron microscope. The 4-point bending test is performed to investigate the strain dependence of electrical resistance. The electron micrograph indicated that tungsten metal clusters with several nanometer size are well dispersed in amorphous carbon host matrix. Based on the electron micrograph, we have modelled electrical transport under strain condition by focusing on two metal clusters separated by the insulating amorphous carbon. The strain dependence of electrical resistance and gauge factor as a function of tungsten metal volume fraction was simulated from this model, and the results were well agreed with the experimental ones. From the model, metal cluster needs to be large for high gauge factor and low TCR in Me-DLC coatings.
